The invention relates to a stand, in particular for a surgical microscope.
A “stand” for purposes of the invention is a floor or wall stand or a ceiling mount.
Surgeons are increasingly making use of surgical microscopes that, because of their heavy weight, must be supported by stands. A number of reputable manufacturers, in addition to the Applicant, have brought to market stands that competently meet the load-bearing requirements of a surgical microscope in mechanical and static terms.
As is known, for example, from DE 101 33 018 A1, many conventional stands—e.g. those for surgical microscopes for ophthalmology—carry at their free end, between the microscope and the vertical stand support, an X and/or Y shifting unit for the microscope. This shifting unit serves for positioning the microscope, within millimeters, in the X and/or Y direction (in the plane parallel to the floor). An arrangement of this kind of the X-Y shifting unit (only the X shifting unit in the case of DE 101 33 018 A1 (FIG. 2)) is usually obtrusive for an operator, since the shifting unit means that a relatively large mass and a large volume must be moved, specifically not only the surgical microscope but also the entire suspension system, pivot support, etc. It is furthermore difficult, with this, to meet the necessary sterility requirements. The X displacement area must in some circumstances be operated by the surgeon, i.e. he or she must access it. This area remote from the surgical field must therefore also be kept completely sterile, which requires a drape. The latter is, however, in turn an impediment to vision and to the operation of controls. The X(-Y) displacement unit furthermore, because of its solid construction, considerably increases the weight on the horizontal extension arm, and as a rule must be compensated for by a corresponding compensation weight or braced by a correspondingly large stand foot. The entire carrier arm structure of the stand support, and if applicable also the entire stand base structure, must consequently have greater dimensions or must be dimensioned with a greater area. This all works against easy operability.
ENT surgical microscopes (microscopes for ear, nose and throat surgery) must be easy to move because a relatively large number of adjustments must be made. In addition, such surgical microscopes need to be fairly economical, since fewer resources are available for ENT surgical operations than in, for example, the neurological sector.
DE 92 19 240 U1 describes a displaceable stand for an optical observation device, having a flange for mounting the displaceable stand onto a stand base, onto an additional stand, or onto the ceiling or a wall. The stand possesses a tilt joint about a horizontal tilt axis and a pivot joint about a pivot axis, by way of which the observation device is received rotatably and/or pivotably on the flange. The pivot joint is connected to the tilt joint with a rigid support extending obliquely downward.
The observation device consequently cannot be displaced in a direction perpendicular to the drawing plane, which greatly limits the positional changes necessary during operation, and therefore the manageability of the observation device.
A “pivot support” is understood as that component or component group which is installed indirectly or directly on the horizontally extending support arm of the stand and receives, via an (in principle, horizontal) horizontal axis (A axis), the optics carrier in which the surgical microscope is held. The optics carrier and thus the surgical microscope are thus pivotable about this horizontal axis (A axis) and are thus intended to be tiltable with reference to that horizontal axis and balanceable preferably in two planes, so that with the brakes released, a surgeon can pivot the optics carrier and thus the surgical microscope about the horizontal axis in as resistance- and torque-free a manner as possible.
The horizontal axis is usually embodied at the lower part of the pivot support and equipped with a braking device or locking device that prevents any unintentional pivoting movement of the optics carrier and thus of the surgical microscope with reference to the pivot support.
The problem set forth in conjunction with DE 92 19 240 U1 is remedied in part by the technical approach described in DE 101 33 018 A1, which presents a stand, in particular for surgical microscopes, that is equipped with a stand base, a vertical support, one or more horizontal supports, a pivot support, and an X-Y-Z displacement unit (FIG. 3) for balancing on the pivot support. Displaceable X, Y, and Z displacement units are provided therein which position the optics carrier, and the microscope body installed thereon, in three dimensions.
In another variant of DE 101 33 018 A1 (FIG. 2), the horizontal displacement unit on which the pivot support can be displaced in a horizontal X direction is arranged not at the free end of the pivot support but on the upper part of the pivot support. This displaceability serves for balancing about an (if applicable) oblique vertical axis (cf. the rigid oblique support of DE 92 19 240 U1) about which the pivot support, and thus the horizontal axis and thus the optics carrier and the microscope, are pivotable. This pivoting movement, too, can be blocked by means of a brake or a locking device. The surgical microscope is thus pivotable in two spatial directions about the axes with the brakes or locking devices released, and can be balanced across the respective pivot axes.
A non-negligible disadvantage of the approach set forth results, however, from the physical dimension of the horizontal displacement unit for X shifting. Shifting of the pivot support in one direction is easily enabled, but this construction blocks or impedes a clear view by the surgical personnel of, for example, important observation areas, or impedes eye contact between surgeons and assistants. The relatively hefty unit also increases the moving mass of the stand, which must be accounted for in the strength calculations for all relevant components.
In the context of so-called “draping,” i.e. covering the entire stand with a sterile cloth, it is also disadvantageous when larger mechanical external accessories are present in the region of the adjusting devices, since the drape can then become even more visually obtrusive.
To ensure better vision for the operator, DE 103 00 620 A1 proposes interconnecting the articulation units at the end of the horizontal support arm with the microscope holder unit via a laterally curved support. Because of its C-shaped appearance, such a support is also called a “C support.” With this approach, an X-Y displacement unit is indeed moved closer to the vertical stand support so that the X-Y positioning unit moves not only the microscope but additionally also part of the horizontal stand support, but this construction also does not yield easy and precise adjustment of the microscope along the aforesaid X direction. Inertia has a very obtrusive effect in this context. This construction therefore also does not possess a complete balancing apparatus for the surgical microscope.
EP 0628290 presents a very complex stand apparatus for an item of medical/optical equipment. It encompasses a pair of vertical parallel links and a pair of horizontal parallel links, which are combined with one another to form a parallelogram support.
An intermediate portion of one of the vertical links is connected pivotably, at a pivot point, to a stand that is arranged on a surface. A counterweight is provided in order to equalize the weight. The parallelogram support is thus equipped so as to hold the medical/optical equipment item in stationary fashion in a floating state. One of the horizontal links of the parallelogram support is elongated in order to form a support link, and a substantially vertical front link is mounted pivotably on the support link at a front end thereof, the medical/optical equipment item being held at the lower end of the front link. The approach that is proposed contributes to easy and precise displacement of the microscope in a vertical direction, but a similar displacement capability in the horizontal direction, i.e. along the X direction, is still not provided.
EP 0917451 B1 describes a pivot support for a surgical microscope on a stand having vertical and horizontal supports with a suspension system. A prerequisite for the approach indicated therein was principally to dispense with parallelogram supports and avoid their disadvantages, and nevertheless to enable torsion-free mounting of a surgical microscope. For that purpose, the parallelogram support was replaced by a combination of two two-armed angled levers, which are rotatably interconnected and which additionally receive at both ends identical lever gearing systems which transfer the moments so that (in a manner comparable to a parallelogram support) the center of gravity of the load can be held in space. The two-armed angled lever is, however, constructed with great complexity from many precise components, and has dimensions approximately comparable to those of the aforementioned X (horizontal) displacement unit of DE 101 33 018 A1.